Aren't you glad you didn't turn on the lights?

Two girls that went to the same college were matched together as roommates. Kate was a socialite who loved to go out to parties and loved guys even more, Jen was a shying wallflower who kept to her studies and had a small group of friends.The two got along most of the time but they didn't see eye to eye when it came to visitors staying over in their room. That night, there was a dorm party on the floor above that they had been invited to. Jen had quickly made her excuses to not go whilst Kate, never one to miss out on a good party, had been planning her outfit since they'd been invited.After the last classes of the day, both girls were in the room. Kate had music playing as she was getting ready for the party and Jen was in her books, studying. A rapid knock on the door alerted them both, almost as soon as the knocking had stopped the door burst open and a group of girls fell in the room laughing. Kate's friends had come round to get ready as a group.Rolling her eyes, Jen picked up her books and declared that she was retreating to the library to continue her studies. Jen sat herself in her favorite comfy chair in the library and began reading her books. Students came and went throughout the night and when she finally closed her books it was close to 2am. Shocked that the time had passed so quickly, she gathered her things and began walking back to her room. As she approached her room door she could hear people inside, sighing, she opened the door and left the light off.  She'd gotten an eyeful on plenty of occasions when she'd interrupted Kate and her 'date' getting amorous in bed. "Nice to know you enjoyed yourself" Jen said. The motions stopped briefly and then carried on again, annoyed that her room mate was ignoring her she changed into her pajamas and climbed into bed. With the noises carrying on she turned on her MP3 player and turned the volume up loud. Quickly, she fell asleep.The next morning she woke to find her MP3 player tangled on her pillow. Picking it up to unravel it, she turned over to scold Kate for her amorous actions the night before. As she turned over she dropped her music player and screamed. Kate was lying in a pool of blood with her sheets over the floor. On the wall, written in blood were the words "Aren't you glad you didn't turn on the lights?"